<!DOCTYPE html>
<html>
<head lang="en">
    <meta charset="UTF-8">
    <title>Leaflet ZoomBox Control</title>
    <link rel="stylesheet" href="//cdn.leafletjs.com/leaflet/v1.0.0/leaflet.css" />
    <link rel="stylesheet" href="L.Control.ZoomBox.css" />
</head>
<body>
    <script src="//cdn.leafletjs.com/leaflet/v1.0.0/leaflet.js"></script>
    <script src="L.Control.ZoomBox.js"></script>
    <div id="map" style="position: absolute; top: 0; left:0; bottom:0; right: 0;"></div>

    <script>
        var map = L.map('map').setView([44.07, -118.78], 6);
        L.tileLayer('//{s}.tile.stamen.com/toner-lite/{z}/{x}/{y}.png', {
            attribution: 'Map tiles by <a href="http://stamen.com">Stamen Design</a>, <a href="http://creativecommons.org/licenses/by/3.0">CC BY 3.0</a> &mdash; Map data &copy; <a href="http://openstreetmap.org">OpenStreetMap</a> contributors, <a href="http://creativecommons.org/licenses/by-sa/2.0/">CC-BY-SA</a>',
            subdomains: 'abcd',
            maxZoom: 10,
            minZoom: 2
        }).addTo(map);

        var control = L.control.zoomBox({modal: true});
        map.addControl(control);
    </script>
</body>
</html>